Balloons Weren’t Alone in the Sky on Eclipse Day

NASA airplanes followed the eclipse's path over North America, flying along the path of totality for seven minutes. During those precious minutes, they glimpsed the outer of the sun and the planet Mercury.

It turns out the research and images collected by students from Lenoir-Rhyne University and the roughly 30 other institutions that took part in NASA’s eclipse balloon launch program weren’t the only high-altitude science projects happening on August 21.

NASA launched a pair of jets from Houston’s Johnson Space Flight Center to follow the eclipse and get a prolonged look at totality, in hopes of learning more about the sun’s corona as well as the planet Mercury. The planes are modified WB-57F jets that date from the 1960’s. The jets cruised at 460 MPH at a height of 50,000 feet (less atmosphere means less distortion to scatter the light) as they followed the eclipse across the center of the nation.

The flight path allowed researchers to experience totality for almost seven minutes. That’s almost 5-and-a-half minutes longer than folks who were stuck on the ground. The planes carried special cameras on turret-like gimbal stabilizers. They locked onto the sun’s image and followed it. During the lengthened totality, a team from NASA’s Goddard Space Flight Center examined the outer part of the Sun to try and figure out why the corona, the plasma aura that extends millions of miles into space, is millions of degrees hotter than the surface of the Sun.

One theory holds that magnetic waves conduct and magnify heat from the surface. There’s another theory that says the extreme heat is created by “nanoflares,” which are tiny explosions on the surface. Researchers hope the high-resolution and high-speed cameras on the jets could capture images that might solve the mystery.

However totality and the sun are only part of the mission. 30 minutes before the moon masked the sun became a rare chance to see the planet Mercury. Normally, Mercury is so close to the Sun in the Earth’s sky that it overwhelmed by its light. But astronomers hoped the eclipse will let them aim infrared cameras at Mercury in hopes of learning more about the planet’s surface. Infrared cameras can penetrate below a planet’s surface to learn how quickly it cools. That will tell scientists what forms the subsurface material. A sandy soil, for example, cools quickly because sand can disperse heat. Rocky soil, on the other hand, is more densely packed and can hold heat longer.

There’s no doubt the research conducted during this total solar eclipse across will spark new questions. Researchers have until 2024, when the path of totality next crosses the U.S., to get their experiments ready.

—Frank Graff

Frank Graff is a producer/reporter with UNC-TV, focusing on Sci Tech NowNorth Carolina, a weekly science series that airs Tuesdays on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog!